Double acting two-stroke cycle engine



Sept. 19, 1961 H. M. EAGLESON DOUBLE ACTING TWO-STROKE CYCLE ENGINE 4 Sheets-Sheet 1 Filed Aug. 17, 1960 INVENTOR. Dr. Hodge M. Eag/eson M By W I HIS ATTORNEYS Se t, 19, 1961 H. M. EAGLESON DOUBLE ACTING TWO-STROKE CYCLE ENGINE 4 Sheets-Sheet 2 Filed Aug. 17, 1960 INVENTOR. DI: Hodge M. Eag/eson 29! W W W HIS ATTORNEYS Sept. 19, 1961 H. M. EAGLESON DOUBLE ACTING TWO-STROKE CYCLE ENGINE 4 Sheets-Sheet 3 Filed Aug. 17, 1960 m gk 3 3 s Q 3 2 w m. F mm 8. i mm on on llllll I: 1

IN VEN TOR. Dr: Hodge M. E agleson W HIS ATTORNEYS Sept. 19, 1961 EAGLESON 3,000,367

DOUBLE ACTING TWO-STROKE CYCLE ENGINE Filed Aug. 1'7, 1960 4 Sheets-Sheet 4 9 INVENTOR.

DI: Hodge M. E ag/eson M, w w

HIS A TTORNE Y5 Patented Sept. 19, 1961 3,000,367 DOUBLE ACTING TWO-STROKE CYCLE ENGINE Hodge M. Eagleson, 1525 State Ave., Coraopolis, Pa. Filed Aug. 17, 1960, Ser. No. 50,137

' 3 Claims. (Cl. 123-53) This application relates to a double acting internal combustion engine with four cylinders or more. These cylinders occupy a compact square-cross-section block and contain a plurality of double acting pistons actuated substantially in concert through parallel paths therein and sharing a common single throw on the crankshaft. Four pistons are illustrated in the present preferred embodiment of the invention although the number must be correspondingly increased when the engine is designed with a larger number of cylinders.

The engine according to the present invention operates with a two-stroke cycle. For the purpose of imparting a lead in both opening and closing to the piston controlled exhaust ports over the piston controlled inlet ports, groups of ports of the first category are provided in a set of adjacent cylinders containing exhaust-portcontrolling pistons of a leading phase and the other groups ports are provided in another set of adjacent cylinders containing inlet-port-controlling pistons which slightly lag with respect to the exhaust-port-controlling pistons. The sets of adjacent cylinders are in parallel disposition arranged one set on each side of the longi tudinal plane through the crankshaft and with the pistons appropriately connected thereto and with an appropriate direction of rotation of the crankshaft.

Inasmuch as the pistons of both sets of cylinders are connected to a single crankshaft throw in common, as already indicated, and by means of a specially constructed connecting rod common thereto, the lead of the exhaust valve controlling pistons over the other pistons is obtained by the varying angularity of the connecting rod, the effect of which provides an earlier closing of the exhaust ports over the inlet ports immediately on passing each dead center position and an earlier opening of the exhaust ports over the inlet ports in the last instants immediately preceding reaching the next dead center position.

The adjacent cylinders of each set are divided by a common division wall extending longitudinally through the square-cross-section block of the present two cycle engine and this wall is of a spaced apart double wall arrangement for receiving the specially constructed connecting rod previously indicated, in the included space therebetween- With this arrangement and the adjunct arrangement whereby the sets of adjacent cylinders are disposed one set on each side of the crankshaft, the objection is minimized that arises with ordinary double acting internal combustion engine owing to the piston rod passing through the center of the crankshaft-adjacent combustion chamber. 'In other words, the cylinders are parallel to one another in a grouping with one at each of the four corners of the cross section of the block so as to straddle both the division wall (i.e. the plane of the connecting rod) and the crankshaft and therefore cylinder heads can be readily aflixed to the block so as to connect all cylinders at each end and without the connecting rod passing through or intruding into any cylinder. r

The four cylinder engine which comprises my invention provides in efiect eight power strokes of the parallel moving pistons per revolution of the single crankshaft throw and in a novel manner solves evident difficulties of the prior art in existence when this invention was made, as will now be explained. Various features, objects and advantages are either specifically explained or will become apparent when for a better understanding of the invention reference is made to the accompanying drawings which form a part hereof and in which:

FIGURE l is a perspective view of a double acting internal combustion engine embodying the present invention;

FIGURE 2 is a schematic view in perspective showing moving parts including the four pistons of the engine of FIGURE 1;

FIGURES 3 and 4 are plan views showing the engine respectively from the outside and in section;

FIGURES 5 and 6 are longitudinal sectional views taken on the section lines VV and VI-VI of FIGURE 3; and

FIGURES 7 and 8 are longitudinal sectional views taken along the lines VII-VII and VIII-VHI of FIG- URE 1.

More particularly in the drawings, the engine has a cylinder block 10 (FIGURES 1, 3 and 4) of generally square cross section and provided with full length water jackets 12. Groups of piston-controlled inlet ports 14 intersect the cylinder walls at spaced apart points along a set of adjacent cylinders 16a and 16b. These ports 14 are supplied with scavenging air under pressure through an intake manifold 18 connected to an engine-driven blower, not shown.

Groups of piston-controlled exhaust ports 20 communicate with another set of adjacent cylinders 22a and 22b. The exhaust ports 20 are connected to a common exhaust manifold 24 supplying an exhaust line 26 leading through a conventional mutfier to atmosphere. A division wall 28 of double wall construction in the block 10 separates the cylinders of each pair of adjacent cylinders from one another.

A pair of pistons 30 (FIGURES 2, 5 and 6) is slidably received in the individual adjacent cylinders 16a and 16b for controlling the inlet ports 14 and a companion pair of exhaust-ports-controlling pistons 32 is slidably received in the individual cylinders 22a and 22b. The pistons 30 and 32 carry rings at both ends so as to be double acting and are provided with the respective wrist pins 34 and 36 connecting them in pairs. A specially shaped flat connecting rod 38 has a T-shaped head portion common to the wrist pins 34 and 36 which are respectively pivoted to one arm 40 of the oppositely extending arms of the T portion and slidably connected by means of a slot to the other arm 42 (FIGURE 2). A crankshaft-adjacent-end of the connecting rod 38 embraces the throw or crank pin 44 of a single throw, loadconnected crankshaft 46 having the usual counter weighted cheeks 48 rigidly supporting the throw pin 44.

The crankshaft 46 (FIGURES 1, 6 and 8) is supported with a rotating fit in main bearings 50 and 52 and is housed oil-tightly by an oil pan 54, the bearings and the oil pan being supported on a common engine base 56 (FIGURE 1). The crankshaft 46 has the usual accessory drive connections for operating fuel injection and water circulation pumps, none being shown, and the crankshaft carries starter gear teeth and the usual flywheel of which only the flywheel 58 is illustrated in FIG- URE l and other figures.

Upper and lower head structures 60 and 62 of the water jacketed type which are afixed by head hold-down bolts 64 to the block 10 define a common combustion or firing chamber 66 in the head at one end of the cylinders and another firing chamber 68 in the head 62 common to said cylinders at their crankshaft-adjacent end. Two spaced apart injectors 72 project through the upper head structure 60 into the common firing chamber 66 with their diagonal axes disposed in a longitudinal plane containing one transverse axis 74 (FIGURE 3) of the head 60. Two injector nozzles 76 extend through the sides of the lower head structure 62 so as to project into the crankshaft-adjacent firing chamber 68 with their common perpendicular axis disposed in a longitudinal plane containing the transverse axis of the head 62. The two-nozzle set 72 and the two-nozzle set 76 are connected in conventional way to be operated in alternation one set to the other by the previously noted injector pump in timed relation to the pistons 30 and 32 at or about their dead center positions corresponding to each firing position.

The transverse axes of the respective cylinder heads just referred to are located in the plane of the division wall 28; in comparing the dimensions of the crankshaftadjacent firing chamber 68 in this plane with the corresponding division wall 28 (FIGURE 5 as supplemented by FIGURE 4), it will be seen that the division wall is not coextensive therewith so that the cylinders 16a and 16b, 22a and 221; are connected for free communication with one another by means of their common firing chamber 68. The cylinders at their opposite end obviously communicate freely through their common firing chamber 66.

The efiect is that the division wall 28 (FIGURE 6) cooperates with the head structure 62 in jointly forming the firing chamber 68 adjacent the crankshaft and at the common joint the head structure 62 has an oifset portion 78 which is inwardly deflected to provide operating clearance for the crank cheeks 48 and the crankshaftadjacent end of the connecting rod 38.

The double wall construction of the division wall 28 provides adequate clearance space accommodating the plane of oscillation of the connecting rod 38 which is received there within. Sets of slots 80 and 82 (FIG- URES 5 and 6) intersect the Walls of the double wall division wall construction so as to enable the common wrist pins 34 and 36 to cross between and pass through the respective adjacent pairs of cylinders.

Removable lubricating oil fittings 84 constantly introduce lubricating oil for the cylinder walls on which the pistons 30 and 32 slide; when these fittings are removed as indicated by the dotted lines in FIGURE 6, rotation of the crankshaft 46 will bring the respective wrist pins 34 and 36 into registry with the threaded openings vacated by the fittings 84. By this means the serviceman is enabled to drive the wrist pins, by means of a drift pin, through the sides of the cylinder for disassembly, service and re-assembly purposes.

In considering the motion of the parts of FIGURE 2, it can readily be visualized that upon rotation of the crankshaft 46 in the direction of the arrow shown, the connecting rod 38 is immediately constrained to tilt whereby the arm 42 of the T portion will take a position of advancement above the level of the opposite arm 40. In this manner on the upward stroke the exhaust port controlling pistons 32 will slightly lead the inlet port controlling pistons 30 so as to close the adjacent group of exhaust ports 20 (FIGURE 5) by a few degrees earlier (in terms of crankshaft rotation) than the corresponding group of the inlet ports 14 is closed; in approaching the other end of the stroke, the pistons 32 will open the other group of exhaust ports 20 by approximately (but not exactly) the same iiumber of degrees earlier than the opening of the corresponding group of inlet ports 14. The slidable connectionin the arm 42 accommodates the pistons 32 in staying concentric to the axes of their respective cylinders as the connecting rod 38 undergoes the tilting motion just de'-,

scribed.

When the connecting rod 38 is moved on the down stroke from its top dead center position shown in FIG- URE 8, the arm 42 and the wrist pin Will lead the other arm and wrist pin 40 and 30 on their down stroke, again closing the adjacent exhaust ports first and thereafter the corresponding group of inlet ports. Similarly, the exhaust ports of the opposite group open'first and thereafter the inlet ports of the opposite group open. The cycle is then repeated,

Making the inlet valve ports late on both strokes enables the residual explosion pressures to dissipate through the earlier opening exhaust valve ports and thus positively initiates momentum of the fluid in the cylinders in that direction prior to induction of the replenishing scavenging air coming from the opposite direction. It also enables the replenishing air, once it starts, to continue to ram into the cylinder for a period after the exhaust ports close, Valve timing of this character means that the engine inherently breathes easier.. This valve timing is fixed, of course, for a given engine but can be varied from engine design to engine design by appropriate selection of the length of the arms 40 and 42, the length of the connecting rod 38, the center to center distance between the cylinders, and/ or the length of stroke determined by the eccentricity of throw of the crankshaft pin 44.

According to the foregoing compact and extremely simple arrangement, an engine is provided having the desirability of a essentially square cross section block utilizing parallel cylinders, and, in terms of a four cylinder engine, has the effectiveness of eight power strokes per crankshaft revolution; moving parts are kept at a minimum owing to only a single crank throw being necessary and it will be obvious that by adding, at appropriate co-planar radial angles, other units with four cylinder blocks as just described it is possible to construct V-engines or X-engines or entirely radial engines in which the cylinders all share the same single throw in common by means of individual T shaped connecting rods connected through a master rod thereto.

' In function, the inlet ports 14 (FIGURE 5) adjacent the firing chamber 66 and the injector nozzles 72 in that chamber provide the air and fuel charge for the firing pressure necessary for actuating the pairs of pistons 30 and 32 substantially in unison on the down stroke Whereas the flywheel, the crankshaft 46, and the Wrist pin connecting rod 38 constitute the necessary inertia means for. continuing movement of the pistons with coordination substantially in unison. The other half of the double action effect is afforded in the upward stroke from the firing pressure provided by air inducted from the inlet ports 14 and the fuel charge from the injectors 76 which serve the crankshaft-adjacent firing chamber 68. Compression ignition principles are utilized in the case of the engine design illustrated although the design is equally well adapted for other firing initiation means such as by spark ignition. In either 'case, a common explosion actuates all pistons in the head structure at one end of their stroke and another common explosion actuates them in the head structure at the opposite end of their stroke.

Variations .within the spirit and scope of the invention described are equally comprehended by the foregoing description. V

I claim: 7 7

1. In a double acting internal combustion engine, a combination comprising an engine block, four separate substantially parallel cylinders disposed'in said block and arranged in adjacent pairs with the cylinders of each adjacent pair having a partition common thereto, a double acting piston in each cylinder with wrist pins connecting said'pistons to form adjacent'pairsj corresponding to said adjacent pairs of cylinders, a first head means atlixedtosaid block and forming a first common firing chamber atthe crankshaft end of said four cylinders, a second head means aflixed to said block and forming a second common firing chamberrfor saidfour cylinders at that end opposite said crankshaft end, a single crankshaft thro-w means, connectin-grod means joinedat one end to said single crankshaft throw means and at the other end to said wrist pins that'said pistons move substantially in unison, means for actuatingsaid pistons to move substantially in unison under firing pressure comprising spaced apart gas ports in said cylinders and at least one fuel injector for each of said first and secnd firing chambers, operation of said fuel injectors being timed to that of said pistons, lubricating means extending through a side of each of said cylinders and disposed in a plane of oscillation of said wrist pins adjacent an end thereof and within limits of their stroke, said lubricating means delivering oil substantially continuously to said pistons during operation of said engine.

2. In a double acting internal combustion engine, a combination comprising an engine block, four separate substantially parallel cylinders disposed in said block and arranged in adjacent pairs, a partition common to the cylinders of each adjacent pair, said partition being double walled to receive therewithin a single connecting rod, a double acting piston in each cylinder with wrist pins connecting said pistons to form adjacent pairs corresponding to said adjacent pairs of cylinders, the wrist pin of each adjacent pair of pistons extending through slots disposed between cylinders of its adjacent pair, said slots being in said double walled partition, a first head means afiixed to said block and forming a first common firing chamber at the crankshaft end of said four cylinders, a second head means affixed to said block and forming a second firing chamber for said four cylinders at that end opposite said crankshaft end, said connecting rod having one end joined to a single crankshaft throw means and having the other end joined to the wrist pins of both pairs of adjacent pistons, means for actuating said pistons to move substantiallyin unison under firing pressure comprising spaced apart gas ports in said cylinder and at least one fuel injector for each of said first and second firing chambers, operation of said fuel injectors being timed to that of said pistons, lubricating means extending through a side of each of said cylinders and disposed in a plane of oscillation of said wrist pins adjacent an end thereof and within limits of their stroke, said lubricating means delivering oil substantially continuously to said pistons during operation of said engine.

3. The connecting rod of claim 2 characterized by a T-shaped head at its end opposite said crankshaft end which head is joined to the wrist pins of both pairs of adjacent pistons.

References Cited in the file of this patent UNITED STATES PATENTS 891,119 Weisenborn June. 16, 1908 926,540 Blomgren June 29, 1913-9 1,471,847 Holliday Oct. 23, 1923 1,649,806 Bronander Nov. 22, 1927 1,876,507 Lee Sept. 6, 1932 FOREIGN PATENTS 147,703 Austria May 21, 1935 

